SoIndexedFaceSet Class Reference
[Shapes]

Indexed polygonal face shape node. More...

#include <Inventor/nodes/SoIndexedFaceSet.h>

Inheritance diagram for SoIndexedFaceSet:

Public Member Functions
virtual SoType	getTypeId () const
	SoIndexedFaceSet ()
Static Public Member Functions
static SoType	getClassTypeId ()

Detailed Description

Indexed polygonal face shape node.

This node represents a 3D shape formed by constructing faces (polygons) from vertices located at the coordinates specified in the vertexProperty field (from SoVertexShape), or the current inherited state. For optimal performance, the vertexProperty field is recommended.

SoIndexedFaceSet is a general purpose polygon rendering node. It can render triangles, quadrilaterals, and other types of polygons or any combination thereof.

Tips:

For best performance, arrange the faces with all triangles first, then all quadrilaterals, then general polygons.
If the shape has only triangles, use SoIndexedTriangleSet instead (simpler and possibly faster).

SoIndexedFaceSet supports both convex and non-convex polygons (unlike OpenGL). However polygons are assumed to be convex by default. Rendering non-convex polygons in this mode may produce incorrect results. Enable non-convex polygons using the faceType field of an SoShapeHints node. In this mode SoIndexedFaceSet will automatically convert non-convex polygons, if necessary, to faces that the hardware can handle.

SoIndexedFaceSet can also directly handle complex polygons with "holes". See the following paragraphs.

If SoShapeHints is not used, or if windingType field from SoShapeHints is equal to NO_WINDING_TYPE, SoIndexedFaceSet uses the indices in the coordIndex field (from SoIndexedShape) to specify simple polygonal faces. An index of SO_END_FACE_INDEX (-1) indicates that the current face has ended and the next one begins.

If SoShapeHints is used with a windingType field other than NO_WINDING_TYPE, SoIndexedFaceSet uses the indices in the coordIndex field (from SoIndexedShape) to specify complex polygonal faces (possibly) made up of multiple contours. An index of SO_END_CONTOUR_INDEX (-1) indicates that the current contour has ended and that the next one begins. An index of SO_END_POLYGON_INDEX (-2) indicates that the current complex face (group of contours) has ended. After the end of a complex face, you can create another complex face, and so on.

Skeleton to create a polygon with holes

   // 1) Choose a winding rule with windingType field from SoShapeHints.

            SoShapeHints *myShapeHints = new SoShapeHints;
            myShapeHints->windingType = SoShapeHints::ODD_TYPE;

   // Create list of contours.

            static int32_t indices[21] =  {
                        0,  3,  1,      SO_END_CONTOUR_INDEX,  
                        5,  6,  4,      SO_END_POLYGON_INDEX, // To end the first polygon.
                        0,  7,  3,      SO_END_CONTOUR_INDEX,
                        10, 9,  8,      SO_END_CONTOUR_INDEX,
                        9,  7,  0,  8,  SO_END_POLYGON_INDEX  // To end the second polygon.
                        };

   // Note: The last polygon must end with either SO_END_POLYGON_INDEX or SO_END_CONTOUR_INDEX or nothing

            static int32_t indices[21] =  {
                        0,  3,  1,      SO_END_CONTOUR_INDEX,  
                        5,  6,  4,      SO_END_POLYGON_INDEX, 
                        0,  7,  3,      SO_END_CONTOUR_INDEX,
                        10, 9,  8,      SO_END_CONTOUR_INDEX,
                        9,  7,  0,  8
                        };

The vertices of the faces are transformed by the current transformation matrix. The faces are drawn with the current light model and drawing style. Diffuse color and opacity may be specified using the orderedRGBA field of SoVertexProperty. Diffuse color, transparency and other color parameters used in the lighting equation may be specified using SoMaterial.

Treatment of the current material and normal binding is as follows: The PER_PART and PER_FACE bindings specify a material or normal for each face. PER_VERTEX specifies a material or normal for each vertex. The corresponding _INDEXED bindings are the same, but use the materialIndex or normalIndex indices (see SoIndexedShape). The default material binding is OVERALL. The default normal binding is PER_VERTEX_INDEXED.

If any normals (or materials) are specified, Open Inventor assumes you provide the correct number of them, as indicated by the binding. You will see unexpected results if you specify fewer normals (or materials) than the shape requires. If no normals are specified, they will be generated automatically.

Lighting is enabled by default (see SoLightModel). If lighting is enabled, by default only the "front face" of polygons are lit (the back face will be black). Which side is the front face is determined by the normal vector, if specified, else by the ordering of the vertices and the vertexOrdering field of SoShapeHints. You can also enable "two sided lighting" using SoShapeHints.

If lighting is enabled and no normals are specified, they will be generated automatically. The normal generator computes "facet" or "smooth" (or a combination) normal vectors depending on the creaseAngle field of SoShapeHints.

Textures may be applied using (for example) SoTexture2. Texture coordinates may be supplied using SoVertexProperty or SoTextureCoordinate2. If a texture is applied and no texture coordinates were specified, they will be computed automatically. By default the computed coordinates map the texture to the axis-aligned bounding box of the shape, with the texture S axis corresponding to the longest axis of the box.

Warning: The shape may not render or pick correctly if any of its polygons are self-intersecting or non-planar.

Limitations:

Currently does not use OpenGL VBOs (vertex buffer objects) for rendering (and performance may be lower) when both texture coordinates and texture coordinate indices are specified. Just setting texture coordinates (indexed by the coordIndex values) is OK.

FILE FORMAT/DEFAULT

vertexProperty	NULL
coordIndex	-1
materialIndex	-1
normalIndex	-1
textureCoordIndex	-1

ACTION BEHAVIOR

SoGLRenderAction

SoRayPickAction
Picks faces based on the current coordinates and transformation. Details about the intersection are returned in an SoFaceDetail.

SoGetBoundingBoxAction
Computes the bounding box that encloses all vertices of the face set with the current transformation applied to them. Sets the center to the average of the coordinates of all vertices.

SoCallbackAction
If any triangle callbacks are registered with the action, they will be invoked for each successive triangle generated from each face in the set.

Constructor & Destructor Documentation

SoIndexedFaceSet::SoIndexedFaceSet ( )

Creates an indexed face set node with default settings.

Member Function Documentation

static SoType SoIndexedFaceSet::getClassTypeId ( ) [static]

Returns the type identifier for this class.

Reimplemented from SoIndexedShape.

Reimplemented in SoGeoElevationGrid, and SoVolumeIndexedFaceSet.

virtual SoType SoIndexedFaceSet::getTypeId ( ) const [virtual]

Returns the type identifier for this specific instance.

Reimplemented from SoIndexedShape.

Reimplemented in SoGeoElevationGrid, and SoVolumeIndexedFaceSet.

The documentation for this class was generated from the following file:

Inventor/nodes/SoIndexedFaceSet.h

SoIndexedFaceSet Class Reference [Shapes]

Public Member Functions